forman Posted February 5, 2015 Share Posted February 5, 2015 Our shock mounts have broken and our right side rear springs are damaged. We have been reinforcing the stock mounts for years, it looks like it is time to address the problem and make the right repair. Which is why I came here to ask for help because I trust that Moses can give me several options, probably before I can research the cheap fix parts I would probably have been guided to by Google. Hear are some of the particulars... This Jeep is weighted by a steel bed liner that could weigh up to 250 pounds. During the summer we use the jeep to carry a chemical spray rig that when full could weigh an additional 600. Up until now all components are stock with a Dana 35 rear end. Wow that is too much weight! I will try to get the owner to remove the steel liner, but I don't think he will. First of all, can we find a solution that will work with the extra weight? Can you recommend a safe procedure that we can follow? I Have questions about the correct way to replace a shock mount using a mig welder. Also what is the correct way to remove replace the rear springs. Thanks! Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 5, 2015 Administrators Share Posted February 5, 2015 Forman...Replacing rear springs is straightforward. Make sure the springs are a full sag (vehicle frame supported by jack stands or a hoist/lift). Loosen the axle/spring U-bolt nuts evenly, this will likely require rust penetrant on the nut threads, and an impact wrench/gun is the best device to use along with impact, deep set sockets. Once the axle is loosened and resting safely on the springs, I like to support the axle with a pair of floor jacks or tripod stands (on a vehicle hoist). All of this can be done without disconnecting the driveline if you're careful: just don't move or rotate the axle housing, or the driveline slip yoke will come out of the transfer case. If the axle is fully supported and safe, you can loosen the springs, at the rear hangers first, lowering the spring eye ends to the floor. When you remove the anchor (front) bolts, the springs will drop and come loose completely. Stay out of harm's way when the spring anchor bolts come loose...Assembly is reverse sequence. I'd like to see some photos of the shock brackets. We'll talk about a variety of repairs. Unless these shocks are spring-overs, they would only break these brackets from severe loads and bottoming out completely. So there's an issue with spring and shock range of motion and travel. Something to consider along with the bracket repair or modifications... Suggestion: Move the 600 lb. sprayer to a trailer if possible. This YJ Wrangler GVWR is equivalent to a 1/4-ton truck. You're at maximum load on a relative light set of springs and a Dana 35 rear axle with only a 7.562" diameter ring gear. (To spread the load between both axles, use 4WD mode with that sprayer in place!) If you must carry this kind of load, consider having the leaf springs beefed up. A 2-inch lift kit with stiffer, higher rate springs would help here. Note: Again, the Dana 35 is only a 7.562" diameter ring gear. The 1990 YJ Wrangler ring gear bolts are terrifyingly small: 3/8"-24 thread! Moses Quote Link to comment Share on other sites More sharing options...
forman Posted February 5, 2015 Author Share Posted February 5, 2015 I don't know if any of these photos need to be explained, you can tell that a hasty field repairs were made until the part failed and needs to be repaired responsibly. What are our options? Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 6, 2015 Administrators Share Posted February 6, 2015 Forman...Thanks for taking photos, looks like you removed the axle without fanfare...As I suspected, the shocks were severely overloaded. I would guess that a set of overload shock/springs were installed at one point. These are shocks with coil springs onboard for added weight carrying capacity. A standard hydraulic shock absorber will never place this kind of burden on the shock brackets. Normally, even gas charged shocks will not stress the OEM shock brackets. If instead the shocks get converted into "springs" and shocks combined, the brackets can wind up looking like this mess. In what I see, either 1) the suspension bottomed so severely that the shocks bottomed out and broke the shock brackets, or 2) the shocks were "overload" style and simply too stiff for the brackets. I would have rear leaf spring stacks custom built for much heavier carrying capacity. This is a common job for a qualified spring shop and not that expensive in the long scheme. The shop will use a much heavier duty main leaf and eyes (must begin here), complemented by a stack of leafs that raise the load capacity at the rear of the vehicle. Of course, this will load the spring anchors, frame and shackles, so there is a limit to how far this approach can go. There are heavy-duty aftermarket spring shackles available, usually with a slight lift built into the design. Avoid spring-over shocks entirely. They are a quick fix and not a good one as you can see. A custom built stiffer spring stack, especially with an empty vehicle, will ride like a buckboard. Here you will need quality shocks to compensate. The shocks must be the correct length (a match for the vehicle's frame and axle brackets) and of good quality. Keep in mind that shocks dampen spring oscillations, that's all they do. They intrinsically do not increase load capacity but simply reduce the risk of spring oscillations. Now to your fragmented brackets. The easiest fix for a weldor would be to carefully cut the existing shock brackets from the axle housing. I would cut the brackets at the metal just outside the factory welds, leaving the factory welds at the axle alone. Find a wrecking yard axle housing from a 1987-95 YJ Wrangler Dana 35, ideally a bare axle of little value. You only need the brackets. Cut the brackets off the scrap axle to match your cuts at the existing axle as closely as practical. Shape these donor brackets closely to enable welding them to your existing axle housing in the stock locations. Make sure the alignment is true before tack welding then finish welding. Clean up the metal surfaces with a milder disc grinder, and MIG weld the brackets into position. Caution: Isolate heat when cutting and welding around an axle! Avoid setting the axle oil on fire internally! Ideally, have both axle housings bare and clean; otherwise, use sound judgment here. If you set this up correctly, the axle and brackets will handle stock or upgrade hydraulic or even gas charged shocks. Gas charged would be an unnecessary cost in this unusual application. Note that when you're done, you have a modified hybrid vehicle. The 1990 YJ Wrangler's frame, anchors and shackles will be bracing against the new and high rate springs. It's understood that there are limits with any system. Here, you're banking on whatever stamina Jeep built into the OEM frame and hangers. The frame, anchors and hangers must survive the 600 pound tank plus the 250 pound bed plate! Moses Quote Link to comment Share on other sites More sharing options...
forman Posted February 6, 2015 Author Share Posted February 6, 2015 While I'm at the wrecking yard if I find a Dana 44 rear end would it fit in place of the dana 35? Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 6, 2015 Administrators Share Posted February 6, 2015 Forman..I see your point. The Dana 35 is way overworked with this load directly on it...The 44 was not common in the YJ Wrangler. You might find a "wide track" 44 from a 1986 CJ, the only year the late CJ used the 44. Measure and compare spring mounting points and other details... There is also the rare MJ Comanche pickup "metric ton" 4x4 with a 44 rear axle. This is the holy grail retrofit for XJ Cherokees. It's also leaf springs but you'd have to compare measurements on overall width (backing plate to backing plate) and the spring perch locations. Note the spring center bolt hole diameter in the perches and the width of the spring perches. The YJ may be a wider perch than the 1986 CJ with a 44. Note that there were also some AMC Model 20 axles in the '86 CJ, all were not Dana 44. 1981-86 Jeep CJ would also be a AMC Model 20 axle. If you decide to change the whole axle, of course you'll also need to match gear ratios front to rear. This narrows the used axle search further. As a footnote, the 44 was popular in I-H, Dodge and vintage Ford trucks. Your YJ Wrangler workhorse is a hybrid, anyway. Maybe you can find a 44 from a Scout or light truck application to work here. Axle ratio is an issue still, and the spring perch locations would need to match up. Track width is of little concern for this vehicle other than tire clearance, and brake sizing is not a major issue, either. Light truck or Scout brakes would be ample. Even a Ford 9-inch axle would be worth considering. You could relocate the spring perches if necessary. Vintage Ford (pre-1957) uses a Spicer 44 and would be a narrower axle width. You'd have adaptation work but could wind up with a heftier rear axle package... Moses Quote Link to comment Share on other sites More sharing options...
forman Posted February 6, 2015 Author Share Posted February 6, 2015 Moses i have quite a learning curve to overcome as I search for a way to resolve my axle issues. Fortunately I found a Dana 35 this morning on Craigslist and I am about to make a short 2 hour drive to check it out... the owner's asking price is a 6 pack. I'll let you know how the trip turned out. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 6, 2015 Administrators Share Posted February 6, 2015 Forman...Considering the low speed use of this vehicle, the easiest fix would be transferring the shock brackets from the donor axle to yours. The custom spring stack solution would buy you the load capacity needed for the tank and bed plate. Look on the door sticker for a rear axle rating, this will be GVWR "Rear Axle" or "RR". This is the actual load that the rear axle can handle. If you have local truck scales and an operator with a sense of humor, weigh the vehicle's rear axle weight. You know the weight of the tank, so you can do this test with just the steel plate in the bed. See what the rear axle is supporting. Use good judgment from there. If you find that the weight on the rear axle is way over gross limit, consider a trailer to mount the tank. This could be easily built from the back section of a truck frame, with or without the bed. You've seen these trailers, I'm sure. You make a yoke from the extended front section of the frame, bending the rails to a "V" point. You get to weld a heavy-duty coupler to the formed yoke. If the truck frame donor is a 3/4-ton with a full-floating axle, you can remove the differential and axle shafts, and simply keep the wheel hub bearings packed—just as you would with a front full-floating hub arrangement like an earlier 4x4 pickup or Jeep models. I like trailering loads. It's so much easier on the tow vehicle! I've never been fond of gooseneck and 5th wheel trailers in pickup beds, either. The 5th wheel load is directly over the rear axle and can reach 1000 pounds or more of added weight on the axle, depending upon trailer size and gross weight. Beyond the axle, consider the tire capacity. You likely need beefier tires at the rear of this Jeep YJ! Make sure the wheel rims have an adequate weight rating, too! Moses Quote Link to comment Share on other sites More sharing options...
forman Posted February 7, 2015 Author Share Posted February 7, 2015 I would like to restore the YJ, and use some other vehicle to carry or pull our spray rig. We have torn up enough equipment over the years using it for what it was not intended. I like your suggestion of removing the shock mounts and attaching them to the original axle. However there is an opportunity to learn about a Dana 35 differential. I would like to be able to inspect the original rear end and know that it is still in good shape or if it needs a rebuild. I plan on reading your fundamental axle rebuilding section of your book Jeep CJ rebuilder's manual again. Also could I get you to write another book entitled the Dana 35 for dummies and send a care package with all the special tools I need : ) . Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 7, 2015 Administrators Share Posted February 7, 2015 I might be arm twisted into sharing a step-by-step rebuild of the Dana 35...Actually, this is a fundamental axle, and the steps for the other Dana axles (30 and 44) apply with only one exception: the Dana 35's crush sleeve on the pinion adjustment. While this sleeve is a major time saver, the new sleeve must be installed correctly. As long as you do not over-crush the sleeve when setting up the pinion bearing preload, the rebuild is straightforward. I can readily provide specs and adjustments for the Jeep Dana 35...If you decide to swap parts over from your "old" axle to the six-pack donor axle housing, we can go from there. You'll change the axle shaft bearings at the same time. None of this is earthshattering, and you have the skill sets for the task at hand! Optimally, the donor axle must have properly set up gears to enable simple math calculations for setting the pinion shim depth. Once the pinion depth and bearing preload are done, the rest of the work proceeds easily. Moses Quote Link to comment Share on other sites More sharing options...
forman Posted February 7, 2015 Author Share Posted February 7, 2015 My donor assembly was mistreated Curiosity got the best of me and I have disassembled the axle and except for the spacers under the clamps pictured. Most of the other gears and spacers fell out when I opened up the case. We would almost be starting from scratch if we swapped gears. I will inspect the original axle sometime next week for a sloppy fit, rust, pitting, abnormal wear. Then make a decision about the gear swap or shock mount swap. I want to do the gear swap because I would like to learn how to do it right. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 7, 2015 Administrators Share Posted February 7, 2015 Forman...Was the differential pin loose or did you loosen it? This would be the support shaft for the smaller "pinions" that rotate around the side gears splined to the axle shafts. It's clear in your photo that the pin is loose. Did you remove the locating bolt for the shaft/pin and start the disassembly? Or did these parts look like this when you removed the diff cover? Were you able to salvage the shock mounting brackets from the six-pack donor axle? Moses Quote Link to comment Share on other sites More sharing options...
forman Posted February 10, 2015 Author Share Posted February 10, 2015 The pin was sheared and all of the parts were loose in the differential. I was able to account for all of the parts and shims. The outer "shell" will need to be cleaned and inspected and yes the shock mounts are in great shape. I would like to use the donor axle assembly Minus the damaged parts with my gear set pending further inspection of both rear ends. If I don't feel confident that I can transfer the gears from the original to the donor I will weld the donor mounts to the original axle and call it good. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 10, 2015 Administrators Share Posted February 10, 2015 With both axles accessible, you're in good shape. Keep in mind that if you do decide to transfer gears over, the pinion depth numbers will need to be determined for proper shimming of a "strange" pinion and ring gear into that donor housing. Not impossible, this can be done mathematically if you decide to do the housing changeover...I'll help at that point if needed. If you like to cut and weld, the shock mount swap will do...Check both housings for straight tubes...The axle end flanges need to be parallel to each other in all directions, you can check this with two straight edges. Keep them parallel with each other as you rotate the straight edges to different clock positions at the axle flange ends. Measure across the housing between the straight edges with a string line or tape measure (achieves ballpark dimensions at least). This will take two people or C-clamps to hold one of the straight edges in position. Moses Quote Link to comment Share on other sites More sharing options...
forman Posted February 15, 2015 Author Share Posted February 15, 2015 Well a week has gone by and my coworkers and myself have had many conversations about the best way for us to proceed with this repair. I wanted to rebuild the donor rear end with the original interior parts, but I lack some tools and knowledge... The donor can be rebuilt later with new parts and I get to learn about that when the time comes. Because we are saving the donor rear end we chose to rebuild the shock mounts and due to the delicate nature of the brackets one of the guys built them out of 1/4" plate steel The donor rear end wasn't a total wash as we will be able to utilize the very new brake assemblies that came on the axle. The original brakes were so far gone due to the lack of maintenance, I don't think they actually worked for several years. Another overlooked lack of maintenance issue was our rear u joints, The needle bearings had fallen completely out but the driveline stayed together for I don't know how long. New leaf springs are on order. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 16, 2015 Administrators Share Posted February 16, 2015 Terrific, Forman...Share with your weldor that he does nice work! Those brackets are very stout and will hold up well. When you get the new springs installed and the driveline ready, check the rear driveline U-joint angles with the vehicle at curb height and the plate in the bed if that's the protocol. (I can cast light on how to measure the U-joint angles with basic tools.) The shocks can be sized for length at that stage. Did you go with a heftier spring rate at stock height? Or did you build the rear spring rate and add rear lift to the vehicle, too? Moses Quote Link to comment Share on other sites More sharing options...
forman Posted February 17, 2015 Author Share Posted February 17, 2015 We ordered heavier springs at stock height, we haven't received them yet. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 17, 2015 Administrators Share Posted February 17, 2015 Forman...This should all help...You have a testimonial in the making with the D35 rear axle and the loads described...Still planning on the 600 lb. tank and 250 lb. plate in the bed? Keep the YJ on dirt and in 4WD mode to distribute the load between rear and front axles... Moses Quote Link to comment Share on other sites More sharing options...
forman Posted April 6, 2015 Author Share Posted April 6, 2015 Update! We were able to finish our axle/ spring/ shock mount/ brakes/ shocks project. The best part was that I was able to involve my coworkers and they were able to learn about the limits of a stock Jeep. Especially one that is as old as this one. Really overall it was a great team building experience. While we were at it we rebuilt the carburetor and discovered that in the previous rebuild the check balls were located in the wrong place. Many thanks Moses! Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted April 6, 2015 Administrators Share Posted April 6, 2015 You're very welcome, Forman! Good news from Texas...Post a few of your great photos, we'd like to see how this YJ Wrangler work Jeep will now be able to tackle that weighty load! Moses Quote Link to comment Share on other sites More sharing options...
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